It’s a good bet that someone’s head at Microsoft is going to roll because of this one: Whether it was an honest mistake--a “technical error”, as Microsoft said in a press release--or some half-baked nefarious plot to cripple Web browser competition, the European Commission is displeased with Microsoft’s failure to comply with a 2009 edict that the company allow users overseas to choose their preferred browser when starting up their Windows machine instead of being handed Internet Explorer by default.

Microsoft had to add a Browser Choice Screen (BCS) on its Windows PCs sold in Europe, and as far as anyone can tell, the company abided by the ruling--until Windows 7 Service Pack 1 was released in February 2011. Apparently, the BCS was missing, and has been until now, for as estimated 28 million users. Worse, Microsoft officially lied about it (whether intentionally or not), stating in a December 2011 report to the EC on the matter that it had maintained compliance.

Nobody in the EC noticed the omission for about a year and a half; recent reports from third parties finally brought it to the group’s attention, which in turn let Microsoft know about it, apparently with both barrels. Microsoft copped to the “technical error” that caused the removal of the BCS in a statement and said that it was conducting an outside investigation into the matter, interviewing employees and looking through documents, and would give a report to the EC.

Image credit: Browserchoice.eu

In a rather heavy-handed statement on the matter, EC VP Joaquin Almunia said, “We are now opening formal proceedings against the company. If following our investigation, this breach is confirmed – and Microsoft seems to acknowledge the facts here – this could have severe consequences. Needless to say, we take compliance with our decision very seriously. If the infringement is confirmed, there will be sanctions.”

Microsoft may be on the hook for some big money here, even though ensuring compliance was evidently a rather low priority for the EC.